In a wireless communication system, such as a third generation partnership project (3GPP) long term evolution (LTE) system, the MAC protocol layer determines whether a transmission resource is available. This mechanism of the MAC protocol determining the transmission opportunity is referred to as scheduling. For a Downlink (DL) transmission, a MAC layer scheduler in an evolved Node B (eNB) may determine when one or more DL packets will be transmitted to a User Equipment (UE). The eNB may transmit a DL scheduling grant to the UE on a Physical Downlink Control Channel (PDCCH) to indicate the DL channel resource for the transmission. For an Uplink (UL) transmission, a UE may request resources for the UL transmission. An UL scheduler within the eNB's MAC layer may decide which UE may have access to the UL channel resources in any given Transmission Time Interval (TTI). The eNB may transmit an UL scheduling grant to the UE on a PDCCH to indicate the UL channel resources for the transmission.
A wireless communication system, such as an LTE system, may also use Discontinuous Reception (DRX) procedures to reduce battery power consumption of a UE in the system. For example, an eNB may configure a UE to operate in a DRX configuration mode by transmitting a DRX configuration to the UE. The DRX configuration may include one or more parameters to indicate when the UE may activate its receiver and monitor a subframe for the presence of DL or UL grants on PDCCH. In some cases, the time when the UE may activate its receiver and monitor PDCCH is referred to as a DRX active time. In some cases, the DL or UL grants are referred to as the DL or UL assignments. During other subframes, the UE may switch off its receiver to reduce power consumption. In some cases, these subframes are referred to as DRX inactive time. The DRX configuration parameters may include one or more timers. The DRX patterns and duty cycles for the DRX active time and the DRX inactive time may vary based on the data activity and the one or more timers. For example, the DRX configuration parameters may include a DRX inactivity timer, which may be set to an initial value and then restarted each time a scheduling grant for either UL or DL is received. When the DRX inactivity timer is running, e.g., during a DRX active time, the UE may actively monitor all DL subframes. When the DRX inactivity timer expires, which may indicate that there has not been any new UL or DL assignments for a defined period of time, the UE's monitoring pattern will change and the UE may monitor only a reduced number of subframes and turn off part or all of its receivers for the remaining downlink subframes to reduce its battery consumption. The eNB may use Radio Resource Control (RRC) messages to transmit the DRX configuration parameters.